Portable mass memories with constantly expanding memory capacity are used increasingly more frequently in very diverse electronic devices. They can store digital contents or text data, image data, audio data or video data or the like. Portable mass memories have the advantage that they can be read and, if applicable, written by different electronic devices such as PCs, PDAs, smart phones, digital cameras, audio devices, etc. The portable mass memories thus permit an easy securing and transporting of digital contents.
For portable mass memories various standards have been developed, whose degree of acceptance varies. Some widespread types of mass memories are multimedia cards (MMC), secure digital memory cards (SD cards), micro-SD cards, memory sticks (USB sticks), but also CDs, DVDs, etc.
It has also already been known to equip portable data carriers of the above-mentioned type additionally with additional functions, particularly security functions, for example in order to protect certain digital contents of the memory against unauthorized access. WO 2006/090393 A2 discloses a method for access by a computer to a peripheral device connected with the computer via a standardized interface. The peripheral device can in particular be a mass memory unit that is connected with the computer via a USB interface and has an additional function, such as an authentication function. For security reasons the usability of operating system functions is limited in principle when accessing the mass memory unit. In order to enable a computer nevertheless to use the otherwise locked operating system functions during a data exchange with a mass memory unit, it is suggested to code corresponding commands in standard-command sequences which do not make any technical sense, but which are recognized and executed by a special application on the mass memory unit. The use of the method requires that suitable unused standard commands exist and that it is not intended to assign a technical effect to the commands used in the method in the long run either. The first is not always given; the second can be a handicap regarding further developments.
From DE 698 15 258 programmable, erasable and non-volatile memories are known that have a read- and/or write-protectable zone, wherein an absolutely determined, memory-independent boundary address delimits the write-protectable zone against the rest of the memory space, and it can be selected on which side of the boundary address the write-protectable zone is to be located. Additionally a protection word can be written in a protection register in order to define the location and size of the write-protectable zone. From EP 1 304 702 furthermore a portable semiconductor memory card and a data reading device in an electronic apparatus are known, by means of which digital contents can be protected. The memory card comprises a re-writable, non-volatile memory with an authentication area and an area not to be authenticated. The memory card additionally comprises a control circuit with a control unit for the area not to be authenticated and an authentication unit executing an authentication process to check whether the electronic apparatus is authorized to access the authentication area via an access control. In doing so the electronic apparatus communicates in an encrypted fashion and the access control decides after decrypting the commands whether the protected area is accessed. These known solutions have the disadvantage that respectively special drivers are required to access a memory card. However, setting up special drivers is work-intensive and impractical, since for different devices with different operating systems respectively particular drivers have to be developed and implemented.
From the “Handbuch für Chipkarten” [Chip-Card Handbook], W. Rankl, W. Effing, 4th edition, Hanser Verlag, Munich, the function and application of smart-card ICs can be gathered. Among other things it contains descriptions of techniques of data transmission to a smart-card IC and methods for memory management.